Title: Properties of Low-Heat Generating Concrete Containing Large Volumes of Blast-Furnace Slag and Fly Ash

Author(s): K. Kanazawa, K. Yamada, and S. Sogo

Publication: Symposium Paper

Volume: 132

Issue:

Appears on pages(s): 97-118

Keywords: adiabatic conditions; blast furnace slag; fly ash; limestone; low-heat cements; mass concrete; slags; strength; water-reducing agents; Materials Research

DOI: 10.14359/1974

Date: 5/1/1992

Abstract:
The anchorages of Akashi Kaikyo Bridge are mass concrete having horizontal dimensions of 60 x 85 m, and a height of 45 m. Precooling and pipe cooling of concrete are used to prevent the thermal cracking of these mass concretes. Furthermore, the low-heat cement has been judged to be more effective to reduce the occurrence of thermal cracks. Comparisons have been made of the basic properties of concrete using a variety of low-heat generating cements to select the ones suitable for the project. The new types of low-heat cement have different ratios of finely ground blast furnace slag, fly ash, and portland cement, and can be broadly divided into binary blended types containing large quantities of slag, and ternary blended types containing large quantities of slag and fly ash. Paper gives results of the strength and adiabatic temperature rise in concrete made using these low-heat-type cements, and the influences of the slag and fly ash on the properties of concrete are described. Although low-heat-generating concrete generally shows retardation in the setting time and shows more bleeding, it was found that the use of very finely ground blast furnace slag and finely ground limestone powder improved workability of concrete, reduced bleeding, and is effective for the development of early-age strength.